Revert^2 "Convert per-test run scripts to python."

This reverts commit 8d6a4e021e1dc4717939e05aee89c9b18e383d12.

Reason for revert: Reland

Test: test.py -r --all-target
Test: diff emitted test commands before and after
Change-Id: I8b99d9b3804615f2ebc50171a4368ad87d809300
diff --git a/test/714-invoke-custom-lambda-metafactory/run b/test/714-invoke-custom-lambda-metafactory/run
index 7a0d0d0..80a8a33 100755
--- a/test/714-invoke-custom-lambda-metafactory/run
+++ b/test/714-invoke-custom-lambda-metafactory/run
@@ -14,6 +14,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# Squash the exit status and put it in expected
-./default-run "$@"
-echo "exit status:" $?
+
+def run(ctx, args):
+  ctx.default_run(args, expected_exit_code=1)